Grade 7 Science Week 4 Session 4

1. What are substances called that change color when they come in contact with an acid or a base?

• a) Bases
  

• b) Indicators
  

• c) Salts
  

• d) Acids

2. Litmus paper, a natural indicator, is obtained from:

• a) Rose petals
  

• b) Turmeric
  

• c) Lichens
  

• d) Beetroot

3. Which statement about acids and bases is correct?

• a) Acids feel slippery, bases taste sour
  

• b) Acids taste sour, bases feel soapy
  

• c) Acids are always dangerous, bases are always safe
  

• d) Acids and bases both turn litmus paper red

4. What are the products of a neutralization reaction?

• a) Gas and water
  

• b) Salt, water, and heat
  

• c) Only water
  

• d) Salt and gas

5. Which acid is injected during an ant bite?

• a) Acetic acid
  

• b) Citric acid
  

• c) Formic acid
  

• d) Tartaric acid

6. What happens when turmeric is added to a basic solution?

• a) Turns yellow
  

• b) Turns green
  

• c) Turns red
  

• d) No change

7. Why do farmers add lime to soil?

• a) To make soil more basic
  

• b) To neutralize acidic soil
  

• c) To kill pests
  

• d) To make soil neutral when it is basic